The present invention relates to surveying instruments and methods for operating surveying instruments. In particular, the invention relates to a surveying instrument, which comprises a measuring system, wherein an inclination angle of the measuring system is adjustable.
For conducting measurements using surveying instruments, it may be necessary to carry out a leveling of a measuring system of the surveying instrument prior to its use. In other words, a predetermined axis of the measuring system is aligned along or perpendicular to the gravity vector. A surveying instrument may for example be a theodolite, a tachymeter (total station, in particular a video tachymeter), a leveling instrument or a laser scanner. However, the present invention is not limited to such devices.
Commonly, bubble levels are used for performing the leveling process. These bubble levels comprise a hollow body or bubble vial, which is made of glass or plastics and which is filled with a liquid and a gas bubble. At the hollow body or bubble vial, marks are provided, which allow to determine the position of the gas bubble within the hollow body or bubble vial. During the leveling process, the inclination of the measuring system is adjusted, until the gas bubble is located at a certain position. Different shapes of bubble levels are available, such as circular levels or bull's eye levels, tubular levels and striding levels.